The present invention relates to a portable heating and cooling unit for use in localized and temporary cooling and heating requirements in buildings, warehouses, computer rooms, and the like. Particularly, the present invention relates. to a portable heating and cooling unit using a refrigerant circuit, and which is mounted in a cabinet supported on wheels.
Portable cooling units are known which are used in localized cooling and heating applications in office buildings, warehouses, computer rooms and the like. The portable cooling units are held within a cabinet which in turn is mounted on caster wheels for mobility. The cooling unit can be placed in near proximity to a particular location which is otherwise not adequately served by the central cooling system of the building or other enclosure. The portable cooling unit can be used to economize on cooling supply in a large structure if only small areas need precise cooling control or extra cooling capacity.
Portable cooling units are useful in localized cooling within a room. The cooling units include a refrigeration circuit which typically includes an evaporator coil, a compressor, a condenser coil and a pressure reducing or expansion valve in a closed circuit containing Freon or other suitable refrigerant. During cooling operation, such a cooling unit draws a first stream of room air past the evaporator coil to cool the air, and passes the thus cooled air back into the room. The cooling unit also draws in a second stream of room air across the condenser coil to condense the refrigerant therein. During condensing of the refrigerant, the second stream of room air is heated and the thus warmed air is directed away from the room area being cooled such as via an exhaust duct. In some cases the warmed air can be discharged simply in a direction away from the cabinet away from the area to be cooled, or can be ducted to the central cooling system return air supply, or to outside of the building.
In some portable cooling units, an electric heating circuit is provided for those occasions when extra heating capacity, rather than cooling capacity, is needed. The heating circuit typically consists of an electric resistance coil wherein a fan circulates room air across the coil to heat the air and pass the air back into the room.
The present invention contemplates a portable cooling and heating unit which includes a reversible refrigerant circuit to alternately provide either cool air or warm air to a room or area of a building. The portable unit includes a cabinet which houses a refrigerant circuit including a first coil and a second coil, a compressor, and valving and accessories to complete the refrigerant circuit. The first coil and the second coil can each alternately serve as evaporator or condenser, depending on whether the unit is being used for heating or cooling. The cabinet also houses fans for drawing room air into the cabinet to be heated or cooled by the first coil and returned to the room, and for drawing room air (heat exchange air) into the cabinet for causing either evaporation or condensing of the refrigerant in the second coil wherein the thus cooled or warm room air is ducted away (or directed away) from the area being cooled or heated.
The cabinet is mounted on caster wheels to be portable within a building or other structure. The discharged heat exchange air, either warm air or cool air, can be ducted by a flexible duct to outside of the room being heated or cooled.
In contrast to prior known portable cooling units, the present invention includes a reversible refrigerant circuit for alternately cooling or heating room air. The refrigerant circuit has a refrigerant flow reversing valve that can be selectively switched to change the unit service from cooling to heating, and the reverse. By reversing the refrigerant""s flow, the first coil and the second coil effectively switch services from evaporator to condenser, or vice versa. By reversing the services of the first and second coils during a switch from cooling to heating service, or vice versa, the first coil can always serve as the room air treating coil while the second coil can always serve as the heat exchange air coil. In this regard, the discharged heat exchange air from the second coil can be ducted away from the area served by a single duct for both alternate heating and cooling periods. Neither the cabinet or the duct need be reversed or reducted for alternate heating or cooling periods.
One or more condensate drip pans are arranged below both the first and second coils. Although a single drip pan can be located below both coils, preferably one drip pan is located below each coil. In accordance with the preferred embodiment cabinet arrangement, the first coil, which serves for alternately heating or cooling room air to be delivered into the room, has a first drip pan which is elevated from a condensate collection tank, and any condensate collected in the first drip pan drains by gravity into the condensate collection tank. A second drip pan for the second coil is arranged at a position lower than the condensate collection tank. A condensate pump is provided in the second drip pan located below the second coil to pump condensate into the condensate collection tank from the second drip pan.
The condensate collection tank can include an automatic shut off system wherein, when the condensate level reaches a maximum in the collection tank, the refrigeration circuit is shut down. The condensate collection tank can be drained continuously by a hose connection to a room drain, or can be drained intermittently by manual drain, for example, by removal of the condensate collection tank and draining of the condensate collected therein. The first coil will typically generate condensate during a cooling operation of the unit, while the second coil will generate condensate during a heating operation of the unit.
According to the invention, an electrical resistance heater is no longer required for the alternate heating mode of the portable heating and cooling unit. The portable heating and cooling unit can thus be efficiently operated as a cooler or a heater by manually reversing the refrigerant circuit. The portable heating and cooling unit is a compact and portable apparatus which effectively heats and cools localized areas within a building, warehouse, computer room and the like. It can be quickly changed in operation from cooling to heating by controls applied onto a front surface of the cabinet. Condensate produced during either a heating or cooling operation is effectively contained within one or more drip pans, and stored in a condensate collection tank for continuous or intermittent disposal.